The gene v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) is associated with a wide variety of cancers, for example, colorectal cancer and non-small cell lung cancer. In particular, cancer may be associated with mutations in codons 12, 13, and 61 of the KRAS gene, namely single nucleotide polymorphisms (SNPs). These SNPs may be indicative of the responsiveness of a subject suffering from cancer to one or more cancer therapies or treatments. In turn, this prediction aides in the selection of the cancer therapy to administer to the subject.
Present assays for detecting these SNPs include amplification-based assays that are capable of detecting multiple SNPs in two reaction mixtures. Such assays, however, do not identify the specific mutation present, but rather only detect if any mutation is or is not present. By failing to identify the identity of the SNPs present or absent, these assays do not allow a user to predict the response of the subject suffering from cancer to one or more cancer therapies, thereby hindering the selection of a cancer therapy for the subject. Other amplification-based assays identify the specific SNP, but to do so, require one reaction mixture per SNP, and thus, require a larger sample input. Samples for diagnostic testing are typically small in size, and therefore, use of a larger amount of sample in one assay limits the ability to test for additional markers in another assay.
Accordingly, a need exists for the development of methods that detect and identify multiple SNPs in the KRAS gene with a minimal amount of sample input to facilitate the prediction of a subject's response to one or more cancer therapies. The identification of particular SNPs for the KRAS gene will further allow practitioners to select the appropriate cancer therapy for the subject.